VARIATION IN TERRESTRIAL HABITAT USE BY FOUR POOL-BREEDING AMPHIBIAN SPECIES

Abstract

We conducted a 2-year study of terrestrial habitat use by spotted salamanders (Ambystoma maculatum), blue-spotted salamanders (A. laterale), wood frogs (Rana sylvatica), and eastern newts (Notophthalmus viridescens) within blocks of forest enclosed by drift fencing and pitfall traps in the vicinity of a single breeding pond. Adult winter densities within forest habitat <100 m from the breeding pond were low for all species (range 0.1–1.9 individuals / 100 m2, n = 6 enclosures). During our 2-year study, at least 40% of wood frogs, 52% of blue-spotted salamanders, and 60% of spotted salamanders wintered >100 m from the breeding pond. Males tended to winter closer to the breeding pond than did females. Adult wood frogs and eastern newts were largely absent from upland forest adjacent to the breeding pond during spring and summer, but they entered these areas in significant numbers to winter. Analyses of net flow of amphibians resulting from fall movement suggest that summer and winter densities of Ambystoma salamanders remained similar, while there were large increases in wood frog and eastern newt densities within terrestrial habitats near the breeding pond during fall. These results support a growing body of evidence that maintenance of suitable terrestrial habitat beyond 100 m from breeding pools is important for maintaining pool-breeding amphibian populations. Narrow protected buffer strips around breeding ponds might be even less effective than previously thought due to the disproportionate representation of males within these areas.